Controlled Release and Taste Masking Oral Pharmaceutical Compositions

ABSTRACT

The invention relates to tablet comprising granules dispersed in at least one hydrophilic compound or matrix. The granules contain an active agent, at least one amphiphilic compound and at least one lipophilic compound. The tablet may include a gastro-resistant film coating.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 14/308,305 filed on Jun. 18, 2014; which is a continuation of application Ser. No. 13/617,138 filed on Sep. 14, 2012, now U.S. Pat. No. 8,784,888; which is a continuation of application Ser. No. 13/462,409 filed on May 2, 2012, now U.S. Pat. No. 8,293,273; which is a continuation of Ser. No. 13/249,839 filed on Sep. 30, 2011, now abandoned; which is a continuation of application Ser. No. 12/210,969 filed on Sep. 15, 2008, which reissued as U.S. Pat. No. RE43,799 from U.S. Pat. No. 8,029,823; which is a continuation-in-part of application Ser. No. 10/009,532 filed on Dec. 12, 2001, now U.S. Pat. No. 7,431,943; which is the 35 U.S.C. 371 national stage of International application PCT/EP00/05356 filed on Jun. 9, 2000; which claimed priority to Italian applications MI2000A000422 and MI99A001317 filed Mar. 3, 2000 and Jun. 14, 1999, respectively. The entire contents of each of the above-identified applications are hereby incorporated by reference.

The present invention relates to controlled release and taste-masking compositions containing one or more active principles incorporated in a three-component matrix structure, i.e. a structure formed by successive amphiphilic, lipophilic or inert matrices and finally incorporated or dispersed in hydrophilic matrices. The use of a plurality of systems for the control of the dissolution of the active ingredient modulates the dissolution rate of the active ingredient in aqueous and/or biological fluids, thereby controlling the release kinetics in the gastrointestinal tract, and it also allows the oral administration of active principles having unfavourable taste characteristics or irritating action on the mucosae of the administration site, particularly in the buccal area.

The compositions of the invention can contain active principles belonging to the therapeutical classes of analgesics, antiinflammatories, cardioactives, tranquillizers, antihypertensives, disinfectants and topical antimicrobials, antiparkinson drugs, antihistamines and are suitable to the oral administration or for acting topically at some areas of the gastrointestinal tract.

TECHNOLOGICAL BACKGROUND

The preparation of a sustained, controlled, delayed or anyhow modified release form can be carried out according to different known techniques:

1. The use of inert matrices, in which the main component of the matrix structure opposes some resistance to the penetration of the solvent due to the poor affinity towards aqueous fluids; such property being known as lipophilia.

2. The use of hydrophilic matrices, in which the main component of the matrix structure opposes high resistance to the progress of the solvent, in that the presence of strongly hydrophilic groups in its chains, mainly branched, remarkably increases viscosity inside the hydrated layer.

3. The use of bioerodible matrices, which are capable of being degraded by the enzymes of some biological compartment.

All the procedures listed above suffer, however, from drawbacks and imperfections.

Inert matrices, for example, generally entail non-linear, but exponential, release of the active ingredient.

Hydrophilic matrices have a linear behaviour until a certain fraction of active ingredient has been released; then they significantly deviate from linear release.

Bioerodible matrices are ideal to carry out the so-called “site-release”, but they involve the problem of finding the suitable enzyme or reactive to degradation. Furthermore, they frequently release in situ metabolites that are not wholly toxicologically inert.

A number of formulations based on inert lipophilic matrices have been described: Drug Dev. Ind. Pharm. 13 (6), 1001-1022, (1987) discloses a process making use of varying amounts of colloidal silica as a porization element for a lipophilic inert matrix in which the active ingredient is incorporated.

The same notion of canalization of an inert matrix is described in U.S. Pat. No. 4,608,248 in which a small amount of a hydrophilic polymer is mixed with the substances forming an inert matrix, in a non sequential compenetration of different matrix materials.

EP 375,063 discloses a technique for the preparation of multiparticulate granules for the controlled-release of the active ingredient which comprises co-dissolution of polymers or suitable substances to form a inert matrix with the active ingredient and the subsequent deposition of said solution on an inert carrier which acts as the core of the device. Alternatively, the inert carrier is kneaded with the solution containing the inert polymer and the active ingredient, then the organic solvent used for the their dissolution is evaporated off to obtain a solid residue. The resulting structure is a “reservoir”, i.e. is not macroscopically homogeneous along all the symmetry axis of the final form.

The same “reservoir” structure is also described in Chem. Pharm. Bull. 46 (3), 531-533, (1998) which improves the application through an annealing technique of the inert polymer layer which is deposited on the surface of the pellets.

To the “reservoir” structure also belong the products obtained according to the technique described in WO 93/00889 which discloses a process for the preparation of pellets in hydrophilic matrix which comprises:

-   -   dissolution of the active ingredient with gastro-resistant         hydrophilic polymers in organic solvents;     -   drying of said suspension;     -   subsequent kneading and formulation of the pellets in a         hydrophilic or lipophilic matrix without distinction of         effectiveness between the two types of application.

EP 0 453 001 discloses a multiparticulate with “reservoir” structure inserted in a hydrophilic matrix. The basic multiparticulate utilizes two coating membranes to decrease the release rate of the active ingredient, a pH-dependent membrane with the purpose of gastric protection and a pH-independent methacrylic membrane with the purpose of slowing down the penetration of the aqueous fluid.

WO 95/16451 discloses a composition only formed by a hydrophilic matrix coated with a gastro-resistant film for controlling the dissolution rate of the active ingredient.

When preparing sustained-, controlled-release dosage forms of a medicament topically active in the gastrointestinal tract, it is important to ensure a controlled release from the first phases following administration, i.e. when the inert matrices have the maximum release rate inside the logarithmic phase, namely the higher deviation from linear release.

Said object has been attained according to the present invention, through the combination of an amphiphilic matrix inside an inert matrix, the latter formulated with a lipophilic polymer in a superficial hydrophilic matrix. The compositions of the invention are characterized by the absence of a first phase in which the medicament superficially present on the matrix is quickly solubilized, and by the fact the amphiphilic layer compensate the lack of affinity of the aqueous solvent with the lipophilic compounds forming the inner inert matrix.

DISCLOSURE OF THE INVENTION

The invention provides controlled release and taste masking oral pharmaceutical compositions containing an active ingredient, comprising:

-   -   a) a matrix consisting of lipophilic compounds with melting         point lower than 90° C. and optionally by amphiphilic compounds         in which the active ingredient is at least partially         incorporated;     -   b) optionally an amphiphilic matrix;     -   c) an outer hydrophilic matrix in which the lipophilic matrix         and the optional amphiphilic matrix are dispersed;     -   d) optionally other excipients.

A particular aspect of the invention consists of controlled release oral compositions containing one or more active ingredients comprising:

-   -   a) a matrix consisting of amphiphilic compounds and lipophilic         compounds with melting point below 90° C. in which the active         ingredient is at least partially incorporated;     -   b) an outer hydrophilic matrix in which the         lipophilic/amphiphilic matrix is dispersed;     -   c) optional other excipients.

A further aspect of the invention provides taste masking oral pharmaceutical compositions containing one or more active ingredients comprising:

-   -   an inert or lipophilic matrix consisting of C6-C20-alcohols or         C8-C20 fatty acids or esters of fatty acids with glycerol or         sorbitol or other polyalcohols with carbon atom chain not higher         than six;     -   an amphiphilic matrix consisting of polar lipids of type I or II         or glycols partially etherified with C1-C4 alkyl chains;     -   an outer hydrophilic matrix containing the above matrices,         mainly formed by saccharide, dextrin, polyalcohol or cellulose         compounds or by hydrogels;     -   optional excipients to give stability to the pharmaceutical         formulation.

DETAILED DISCLOSURE OF THE INVENTION

The compositions of the invention can be prepared by a method comprising the following steps:

-   -   a) the active ingredient is first inglobated by simple kneading         or mixing in a matrix or coating consisting of compounds having         amphiphilic properties, which will be further specified below.         The active principle(s) can be mixed with the amphiphilic         compounds without the aid of solvents or with small amounts of         water-alcoholic solvents.     -   b) The matrix obtained in a) is incorporated in a low melting         lipophilic excipient or mixture of excipients, while heating to         soften and/or melt the excipient itself, which thereby         incorporates the active ingredient by simple dispersion. After         cooling at room temperature an inert matrix forms, which can be         reduced in size to obtain inert matrix granules containing the         active ingredient particles.     -   c) The inert matrix granules are subsequently mixed together         with one or more hydrophilic water-swellable excipients. The         mixture is then subjected to compression or tabletting. This         way, when the tablet is contacted with biological fluids, a high         viscosity swollen layer is formed, which coordinates the solvent         molecules and acts as a barrier to penetration of the aqueous         fluid itself inside the new structure. Said barrier antagonizes         the starting “burst effect” caused by the dissolution of the         medicament inglobated inside the inert matrix, which is in its         turn inside the hydrophilic matrix.

The amphiphilic compounds which can be used according to the invention comprise polar lipids of type I or II (lecithin, phosphatidylcholine, phosphatidylethanolamine), ceramides, glycol alkyl ethers such as diethylene glycol monomethyl ether (Transcutol®).

The lipophilic matrix consists of substances selected from unsaturated or hydrogenated alcohols or fatty acids, salts, esters or amides thereof, fatty acids mono-, di- or triglycerides, the polyethoxylated derivatives thereof, waxes, ceramides, cholesterol derivatives or mixtures thereof having a melting point within the range of 40 to 90° C., preferably from 60 to 70° C.

If desired, a fatty acid calcium salt may be incorporated in the lipophilic matrix which is subsequently dispersed in a hydrophilic matrix prepared with alginic acid, thus remarkably increasing the hydrophilic matrix viscosity following penetration of the solvent front until contact with the lipophilic matrix granules dispersed inside.

According to an embodiment of the invention, an amphiphilic matrix with high content in active ingredient, typically from 5 to 95% w/w, is first prepared by dispersing the active ingredient or the mixture of active ingredients in a mixture of amphiphilic compounds, such as lecithin, other type II polar lipids, surfactants, or in diethylene glycol monoethyl ether; the resulting amphiphilic matrix is then mixed or kneaded, usually while hot, with lipophilic compounds suitable to form an inert matrix, such as saturated or unsaturated fatty acids, such as palmitic, stearic, myristic, lauric, laurylic, or oleic acids or mixtures thereof with other fatty acids with shorter chain, or salts or alcohols or derivatives of the cited fatty acids, such as mono-, di-, or triglycerides or esters with polyethylene glycols, alone or in combination with waxes, ceramides, cholesterol derivatives or other apolar lipids in various ratios so that the melting or softening points of the lipophilic compounds mixtures is within the range of 40 to 90° C., preferably from 60 to 70° C.

Alternatively, the order of formation of the inert and amphiphilic matrices can be reversed, incorporating the inert matrix inside the amphiphilic compounds.

The resulting inert lipophilic matrix is reduced into granules by an extrusion and/or granulation process, or any other known processes which retain the homogeneous dispersion and matrix structure of the starting mixture.

The hydrophilic matrix consists of excipients known as hydrogels, i.e. substances which when passing from the dry state to the hydrated one, undergo the so-called “molecular relaxation”, namely a remarkable increase in mass and weight following the coordination of a large number of water molecules by the polar groups present in the polymeric chains of the excipients themselves.

Examples of hydrogels which can be used according to the invention are compounds selected from acrylic or methacrylic acid polymers or copolymers, alkylvinyl polymers, hydroxyalkyl celluloses, carboxyalkyl celluloses, polysaccharides, dextrins, pectins, starches and derivatives, natural or synthetic gums, alginic acid.

In case of taste-masking formulations, the use of polyalcohols such as xylitol, maltitol and mannitol as hydrophilic compounds can also be advantageous.

The lipophilic matrix granules containing the active ingredient are mixed with the hydrophilic compounds cited above in a weight ratio typically ranging from 100:0.5 to 100:50 (lipophilic matrix:hydrophilic matrix). Part of the active ingredient can optionally be mixed with hydrophilic substances to provide compositions in which the active ingredient is dispersed both in the lipophilic and the hydrophilic matrix, said compositions being preferably in the form of tablets, capsules and/or minitablets.

The compression of the mixture of lipophilic and/or amphiphilic matrix, hydrogel-forming compound and, optionally, active ingredient not inglobated in the lipophilic matrix, yields a macroscopically homogeneous structure in all its volume, namely a matrix containing a dispersion of the lipophilic granules in a hydrophilic matrix. A similar result can also be obtained by coating the lipophilic matrix granules with a hydrophilic polymer coating.

The tablets obtainable according to the invention can optionally be subjected to known coating processes with a gastro-resistant film, consisting of, for example, methacrylic acids polymers (Eudragit®) or cellulose derivatives, such as cellulose acetophthalate.

Active ingredients which can conveniently be formulated according to the invention comprise:

analgesics, such as acetaminophen, phenacetin, sodium salicylate; antitussives, such as dextromethorphan, codeine phosphate;

bronchodilators, such as albuterol, procaterol;

antipsychotics, such as haloperidol, chlorpromazine;

antihypertensives and coronary-dilators, such as isosorbide mono- and dinitrate, captopril;

selective β2 antagonists such as salbutamol, terbutaline, ephedrine, orciprenaline sulfate;

calcium antagonists, such as nifedipine, nicardipine, diltiazem, verapamil;

antiparkinson drugs, such as pergolide, carpidopa, levodopa;

non steroid anti-inflammatory drugs, such as ketoprofen, ibuprofen, diclofenac, diflunisal, piroxicam, naproxen, ketorolac, nimesulide, thiaprophenic acid, mesalazine (5-aminosalicylic acid); antihistamines, such as terfenedine, loratadine;

antidiarrheals and intestinal antiinflammatories, such as loperamide, 5-aminosalicylic, olsalazine, sulfasalazine, budenoside;

spasmolytics such as octylonium bromide;

anxiolytics, such as chlordiazepoxide, oxazepam, medazepam, alprazolam, donazepam, lorazepan;

oral antidiabetics, such as glipizide, metformin, phenformin, gilclazide, glibenclamide;

cathartics, such as bisacodil, sodium picosulfate;

antiepileptics, such as valproate, carbamazepine, phenyloin, gabapentin;

antitumorals, such as flutamide, etoposide;

oral cavity disinfectants or antimicrobials, such as benzalkonium chloride, cetylpyridinium chloride or tibezonium iodide, and some amino derivatives such as benzydamine and chlorhexidine as well as the salts and derivatives thereof;

sodium fluoride.

The compositions of the invention can further contain conventional excipients, for example bioadhesive excipients such as chitosans, polyacrylamides, natural or synthetic gums, acrylic acid polymers.

The compositions of the invention can contain more than one active ingredient, each of them being optionally contained in the hydrophilic matrix or in the inert amphiphilic matrix, and are preferably in the form of tablets, capsules or minitablets.

In terms of dissolution characteristics, contact with water or aqueous fluids causes the immediate penetration of water inside the more superficial layer of the matrix which, thanks to the presence of the aqueous solvent, swells due to the distension of the polymeric chains of the hydrogels, giving rise to a high viscosity hydrated front which prevents the further penetration of the solvent itself linearly slowing down the dissolution process to a well determined point which can be located at about half the thickness, until the further penetration of water would cause the disintegration of the hydrophilic layer and therefore the release of the content which, consisting of inert matrix granules, however induces the diffusion mechanism typical of these structures and therefore further slows down the dissolution profile of the active ingredient.

The presence of the amphiphilic matrix inside the lipophilic matrix inert allows to prevent any unevenness of the release profile of the active ingredient. The surfactants present in the amphiphilic portion promote wettability of the porous canaliculuses which cross the inert matrix preventing or reducing resistance to penetration of the solvent inside the inert matrix.

To obtain taste masking tablets, the components of the hydrophilic matrix are carefully selected to minimize the active substance release time through penetration accelerated by the canalization induced by the hydrophilic compound.

The following Examples illustrate the invention in greater detail.

EXAMPLE 1

500 g of 5-aminosalicylic-acid and 20 g of octylonium bromide are mixed with 10 g of soy lecithin dissolved in 50 g of a water:ethyl alcohol 1:3 mixture at about 50° C. After homogenization and drying, the granules of the resulting matrix are treated in a kneader with 20 g of carnauba wax and 50 g of stearic acid, heating until homogeneous dispersion, then cold-extruded into small granules. The inert matrix granules are loaded into a mixer in which 30 g of carbopol 971 P and 65 g of hydroxypropyl methylcellulose are sequentially added. After a first mixing step for homogeneously dispersing the powders, 60 g of microcrystalline cellulose and 5 g of magnesium stearate are added. After mixing, the final mixture is tabletted to unitary weight of 760 mg/tablet. The resulting tablets are film-coated with cellulose acetophthalate or polymethacrylates and a plasticizer to provide gastric resistance and prevent the early release of product in the stomach.

The resulting tablets, when subjected to dissolution test in simulated enteric juice, have shown a release of the active principles having the following profile: after 60 minutes no more than 30%, after 180 minutes no more than 60%, after 5 hours no more than 80%.

EXAMPLE 2

50 g of diethylene glycol monoethyl ether are homogeneously distributed on 500 g of microcrystalline cellulose; then 100 g of Budesonide are added, mixing to complete homogenization. This mix is further added with 400 g of Budesonide, then dispersed in a blender containing 100 g of carnauba wax and 100 g of stearic acid preheated at a temperature of 60° C. After kneading for 5 minutes, the mixture is cooled to room temperature and extruded in granules of size below 1 mm.

A suitable mixer is loaded with the matrix granules prepared as above and the following amounts of hydrophilic excipients: 1500 g of hydroxypropyl methylcellulose and 500 g of policarbophil.

The components are mixed until homogeneous dispersion of the matrices, then added with 2450 g of microcrystalline cellulose, 400 g of lactose, 100 g of colloidal silica and 50 g of magnesium stearate. After further 5 minute mixing, the mix is tabletted to unitary weight of 250 mg/tablet.

EXAMPLE 3

850 g of metformin are dispersed in a granulator/kneader with 35 g of diethylene glycol monoethyl ether previously melted with 100 g of stearic acid and 55 g of carnauba wax. The system is heated to carry out the granulation of the active ingredient in the inert matrix. The resulting 1040 g of formulation are added with 110 g of hydroxypropyl methylcellulose and 20 g of magnesium stearate.

The final mixture is tabletted to unitary weight of 1170 mg/tablet equivalent to 850 mg of active ingredient.

The resulting tablets, when subjected to dissolution test in simulated enteric juice, have shown a release of the active principles having the following profile: after 60 minutes no more than 35%, after 180 minutes no more than 60%, after 5 hours no more than 80%.

EXAMPLE 4

120 g of octylonium bromide are dispersed in a granulator/kneader with 30 g of stearic acid and 15 g of beeswax in which 10 g of diethylene glycol monoethylene had previously been melted.

The system is heated to carry out the granulation of the active ingredient in the inert matrix. The resulting 10 g of formulation are added with 5 g of hydroxypropyl methylcellulose and 5 g of policarbophyl, 2 g of magnesium stearate and 3 g of microcrystalline cellulose.

The final mixture is tabletted to unitary weight of 200 mg/tablet equivalent to 120 mg of active ingredient.

The resulting tablets, when subjected to dissolution test in simulated enteric juice, have shown a release of the active principles having the following profile: after 60 minutes no more than 25%; after 180 minutes no more than 50%; after 5 hours no more than 70%.

EXAMPLE 5

12 g of diethylene glycol monoethyl ether are loaded on 6 g of microcrystalline cellulose and 6 grams of calcium carbonate, then 100 g of Gabapentin are added and the mixture is homogenized. After that, 800 g of Gabapentin are added which are dispersed in a granulator/kneader with 4.5 g of white wax and 5 g of stearic acid. The system is heated to carry out the granulation of the active ingredient in the inert matrix. The resulting 916.5 g of formulation are added with 39.5 g of hydroxypropyl methylcellulose, 10 g of alginic acid, 11 g of magnesium stearate and 6 g of syloid. The final mixture is tabletted to unitary weight of 1000 mg/tablet equivalent to 900 mg of active ingredient.

EXAMPLE 6

50 g (25 g) of carbidopa and 200 g (100 g) of levodopa are dispersed in a granulator/kneader with 60 g (30 g) of stearic acid and 30 g (15 g) of yellow wax, in which 10 (5) g of diethylene glycol monoethyl ether had previously been melted.

The system is heated to carry out the granulation of the active ingredient in the inert matrix. The resulting 340 g (170 g) of formulation are added with 20 g (10 g) of hydroxypropyl methylcellulose, 10 g (5 g) of xantangum, 16 g (8 g) of microcrystalline cellulose, 4 g (2 g) of magnesium stearate.

The final mixture is tabletted to unitary weight of 400 (200) mg/tablet equivalent to 50 (25) mg of carbidopa and 200 (100) mg di levodopa.

EXAMPLE 7

4 g of Nimesulide are solubilised in 50 g of diethylene glycol monoethyl ether, then 100 g of microcrystalline cellulose are added to obtain a homogeneous mixture.

The resulting mixture is added in a granulator/kneader with 196 g of Nimesulide, 50 g of stearic acid and 25 g of carnauba wax. The system is heated to carry out the granulation of the active ingredient in the inert and amphiphilic matrix system.

425 g of the resulting granulate are added with 60 g of hydroxypropyl methylcellulose, 5 g of policarbophil and 10 g of magnesium stearate.

The final mixture is tabletted to unitary weight of 500 mg/tablet equivalent to 200 mg of active ingredient.

The resulting tablets, when subjected to dissolution test in simulated enteric juice, have shown a release of the active principles having the following profile: after 1 hour no more than 25%, after 2 hours no more than 40%, after 4 hours no more than 60%, after 8 hours no more than 90%.

EXAMPLE 8

500 g of propionyl carnitine are dispersed in a granulator/kneader with 90 g of stearic acid and 40 g of carnauba wax, in which 20 g of diethylene glycol monoethyl ether had previously been melted. The system is heated to carry out the granulation of the active ingredient in the inert/amphiphilic matrix. The resulting 650 g of formulation are added with 60 g of hydroxypropyl methylcellulose and 10 g of magnesium stearate.

The final mixture is tabletted to unitary weight of 720 mg/tablet equivalent to 500 mg of active ingredient.

The resulting tablets, when subjected to dissolution test in simulated enteric juice, have shown a release of the active principles having the following profile: after 60 minutes no more than 40%, after 180 minutes no more than 60%, after 4 hours no more than 80%, after 8 hours no more than 90%.

EXAMPLE 9

One kg of Nimesulide is placed in a high rate granulator, pre-heated to about 70°, together with 200 g of cetyl alcohol and 25 g of glycerol palmitostearate the mixture is kneaded for about 15 minutes and stirred while decreasing temperature to about 30° C. The resulting inert matrix is added, keeping stirring and kneading during cooling, with 50 g of soy lecithin and 50 g of ethylene glycol monoethyl ether. The granulate is extruded through a metallic screen of suitable size and mixed with 50 g of hydroxypropyl methylcellulose, 1320 kg of maltodextrins, 2 kg of lactose-cellulose mixture, 50 g of colloidal silica, 40 g of aspartame, 150 g of citric acid, 75 g of flavour and 65 g of magnesium stearate. The final mixture is tabletted to unitary weight of about 500 mg, having hardness suitable for being dissolved in the mouth and a pleasant taste.

EXAMPLE 10

Operating as in the preceding example, chewable tablets are prepared replacing dextrin with mannitol and the lactose-cellulose mixture with xylitol. The resulting tablets have pleasant taste and give upon chewing a sensation of freshness enhancing the flavour.

EXAMPLE 11

Operating as described in example 9, but with the following components:

active ingredient: ibuprofen mg 100 lipophilic/inert matrix component: mg 15 cetyl alcohol amphiphilic matrix component: soy lecithin mg 8 hydrophilic matrix components: mannitol mg 167 maltodextrins mg 150 methylhydroxypropylcellulose mg 30 adjuvants: aspartame mg 15 flavour mg 5 colloidal silica mg 5 magnesium stearate mg 5

500 mg unitary weight tablets are obtained, which undergo progressive erosion upon buccal administration, and effectively mask the bitter, irritating taste of the active ingredient.

EXAMPLE 12

Operating as described in example 9, but with the following components:

active ingredient: diclofenac sodium mg 25 lipophilic/inert matrix component: mg 5 cetyl alcohol glycerol palmitostearate mg 5 amphiphilic matrix component: mg 7 soy lecithin hydrophilic matrix components: xylitol mg 168 maltodextrins mg 150 hydroxypropylmethylcellulose mg 20 adjuvants: aspartame mg 5 flavour mg 5 colloidal silica mg 5 magnesium stearate mg 5

400 mg unitary weight tablets are obtained, which undergo progressive erosion upon buccal administration, and effectively mask the irritating taste of the active ingredient.

EXAMPLE 13

Operating as described in example 9, but with the following components:

active ingredient: chlorhexidine mg 2.5 lipophilic/inert matrix component: mg 0.5 cetyl alcohol glycerol palmitostearate mg 0.5 amphiphilic matrix component: mg 0.3 diethylene glycol monoethyl ether hydrophilic matrix components: xylitol mg 38 maltodextrins mg 96 hydroxypropyl methylcellulose mg 10 adjuvants: aspartame mg 3 flavour mg 5 colloidal silica mg 2 magnesium stearate mg 2

150 mg unitary weight tablets are obtained, which undergo progressive erosion upon buccal administration, and effectively mask the irritating taste of the active ingredient.

EXAMPLE 14

One Kg of Nimesulide is placed in a high rate granulator, pre-heated to about 70°, together with g 125 of cetyl alcohol: the mixture is kneaded for about 15 minutes and stirred while decreasing temperature to about 30° C., then added with g 30 of lecithin. The resulting matrix is then extruded through a metallic screen of suitable size and mixed with 2.415 kg of lactose, 1.0 kg of maltodextrins, 50 g of hydroxypropyl methylcellulose, 50 g of colloidal silica, 40 g of aspartame, 150 g of citric acid, 75 g of flavour and 65 g of magnesium stearate. The final mixture is tabletted to about 500 mg tablets, having hardness suitable for being dissolved in the mouth and pleasant taste. 

1. An oral dosage form for the controlled release of an active ingredient in the gastrointestinal tract of a human, said oral dosage form comprising: (i) an inert or lipophilic matrix comprising the active ingredient and an amphiphilic compound; and (ii) a hydrophilic matrix, wherein the inert or lipophilic matrix is dispersed in the hydrophilic matrix.
 2. The oral dosage form according to claim 1, wherein the active ingredient is budesonide.
 3. The oral dosage form according to claim 1, wherein said tablet further comprises a gastro-resistant coating.
 4. The oral dosage form according to claim 1, wherein the gastro-resistant coating comprises a compound selected from methacrylic acid polymers and cellulose derivatives.
 5. The oral dosage form according to claim 4, wherein the gastro-resistant coating comprises a methacrylic acid polymer.
 6. The oral dosage form according to claim 1, wherein the amphiphilic compound is selected from the group consisting of lecithin, phosphatidylcholine, phosphatidylethanolamine, ceramide, and a glycol alkyl ether.
 7. The oral dosage form according to claim 6, wherein the amphiphilic compound is lecithin.
 8. The oral dosage form according to claim 1, wherein the inert or lipophilic matrix comprises a compound selected from the group consisting of saturated or unsaturated fatty acid, salt, or alcohol thereof; a mono-, di-, or triglyceride, or polyethoxylated derivative thereof, a wax, ceramide, and cholesterol derivative.
 9. The oral dosage form according to claim 8, wherein the inert or lipophilic matrix comprises a saturated fatty acid.
 10. The oral dosage form according to claim 9, wherein the inert or lipophilic matrix comprises stearic acid.
 11. The oral dosage form according to claim 1, wherein the hydrophilic matrix comprises one or more water-swellable excipients.
 12. The oral dosage form according to claim 1, wherein the hydrophilic matrix comprises a compound selected from the group consisting of an acrylic or methacrylic acid polymer or copolymer, an alkylvinyl polymer, hydroxyalkyl cellulose, a carboxyalkyl cellulose, a polysaccharide, dextrin, pectin, starch, a natural or synthetic gum, and alginic acid.
 13. The oral dosage form according to claim 12, wherein the hydrophilic matrix comprises a hydroxyalkyl cellulose or a carboxylalkyl cellulose.
 14. The oral dosage form according to claim 13, wherein the hydrophilic matrix comprises a hydroxyalkyl cellulose.
 15. An oral dosage form for the controlled release of budesonide in the gastrointestinal tract of a human, said oral dosage form comprising: (i) an inert or lipophilic matrix comprising budesonide and an amphiphilic compound; and (ii) a first matrix comprising a hydrophilic compound, wherein the inert or lipophilic matrix is dispersed in the first matrix.
 16. The oral dosage form according to claim 15, wherein said tablet further comprises a gastro-resistant coating.
 17. The oral dosage form according to claim 15, wherein the gastro-resistant coating comprises a compound selected from methacrylic acid polymers and cellulose derivatives.
 18. The oral dosage form according to claim 17, wherein the gastro-resistant coating comprises a methacrylic acid polymer.
 19. The oral dosage form according to claim 15, wherein the amphiphilic compound is selected from the group consisting of lecithin, phosphatidylcholine, phosphatidylethanolamine, ceramide, and a glycol alkyl ether.
 20. The oral dosage form according to claim 19, wherein the amphiphilic compound is lecithin.
 21. The oral dosage form according to claim 15, wherein the inert or lipophilic matrix comprises a compound selected from the group consisting of saturated or unsaturated fatty acid, salt, or alcohol thereof; a mono-, di-, or triglyceride, or polyethoxylated derivative thereof, a wax, ceramide, and cholesterol derivative.
 22. The oral dosage form according to claim 21, wherein the inert or lipophilic matrix comprises a saturated fatty acid.
 23. The oral dosage form according to claim 22, wherein the inert or lipophilic matrix comprises stearic acid.
 24. The oral dosage form according to claim 15, wherein the hydrophilic compound is a water-swellable excipient.
 25. The oral dosage form according to claim 15, wherein the hydrophilic compound is selected from the group consisting of an acrylic or methacrylic acid polymer or copolymer, an alkylvinyl polymer, hydroxyalkyl cellulose, a carboxyalkyl cellulose, a polysaccharide, dextrin, pectin, starch, a natural or synthetic gum, and alginic acid.
 26. The oral dosage form according to claim 25, wherein the hydrophilic compound is hydroxyalkyl cellulose or carboxylalkyl cellulose.
 27. The oral dosage form according to claim 26, wherein the hydrophilic compound is hydroxyalkyl cellulose.
 28. An oral dosage form for the controlled release of budesonide in the gastrointestinal tract of a human, said oral dosage form comprising: a plurality of inert or lipophilic matrices dispersed in a hydrophilic matrix, wherein each of the inert or lipophilic matrices incorporates a first matrix comprising budesonide and an amphiphilic compound.
 29. An oral dosage form for the controlled release of budesonide in the gastrointestinal tract of a human, said oral dosage form comprising: a plurality of inert or lipophilic matrices dispersed in a first matrix comprising a hydrophilic compound, wherein each of the inert or lipophilic matrices incorporates budesonide and an amphiphilic compound.
 30. The oral dosage form according to claim 29, wherein the first matrix is a hydrophilic matrix. 